1. a type of cargo boat found in the past on the rivers Severn and Wye in Great Britain and used to transport goods.
2. In the folkloric traditions of the Orkney and Shetland islands, a trow (alternatively trowe or drow) is a small, troll-like fairy creature.
3. Archaic . to believe, think, or suppose.

[Middle English trowen, from Old English trowian, to trust; see deru- in Indo-European roots.]

(I'll include definitions for old, unusual or archaic words. Thus, we Whites can continue to improve our vocabulary.)